This invention relates in general to fan jet gas turbine engines and, more specifically, to a system for supporting the aft engine of the engine against bending forces.
In conventional fan jet engines of the sort used in large commercial aircraft, the engine cowling is supported within the engine nacelle near the front through an annular array of struts. Since the engine is relatively narrow and "wasp waisted", it is subject to bending and flexing in operation causing a number of problems, such as metal fatigue, fastener loosening, etc. Also, these movements can lead to increased turbine blade clearances and lower engine efficiency with resulting lower fuel efficiency.
Attempts have been made to reduce bending and flexing by adding supports near the aft end of the engine. Such supports have a number of problems accommodating the radial and longitudinal thermal expansion of the engine during operation. Prior supports tend to be heavy and complex, adding fuel consuming weight to the aircraft and adding opportunity for errors in mounting the engine and potential for failures in operation.
Typical of these proposed aft engine supports is the complex system of annular teeth and grooves with radial pins and ball joints described by Naud in U.S. Pat. No. 4,683,717 and the complex system described by Pachomoff et al in U.S. Pat. No. 4,742,975 which requires the addition of safety rods to protect against failure of the support system.
Thus, there is a continuing need for an engine support system which is simple, light weight and accommodates radial and longitudinal engine thermal expansion during use.